Room: Exhibit Hall | Forum 3
Purpose: To investigate the correlation of microscopic skin dose, incurred via Strontium-90 beta radiation exposure, with the progression of cutaneous radiation injury (CRI) in an animal model used to study the efficacy of medical countermeasures against radiation.
Methods: A custom-made Strontium-90 beta-ray source was used to irradiate pig skin at designated target sites with a single-fraction dose of 37 Gy. Histological samples were collected at the injury sites at 70 days post-irradiation. Spatial analysis of the epidermal necrosis expression was correlated with beta-ray dose profiles at depths of various skin layers. Two basic dosimetry models are being implemented to investigate the microscopic dose delivery to the structural components of the skin: 1) analytical and 2) Monte-Carlo. Analytical planar source models include the Loevinger-Cross, Vynckier-Wambersie and Morgan-Emerson models. Monte Carlo simulations include single- and 7-source models of the unique beta-ray device, using the MCNP6 code (Oak Ridge National Laboratory) coupled with representations of skin geometry and its tissue components. Results are compared to radiochromic film and extrapolation chamber dose measurements and correlated with histological findings of epidermal and dermal necrosis.
Results: Of the three analytical models, the Morgan-Emerson model shows best agreement with measured dose (extrapolation chamber), however, the validity of these analytical models remains questionable. In comparison, the Monte-Carlo model shows promise as a good match to the experimentally measured surface skin dose.
Conclusion: The intricacies of the microscopic dose distribution in the upper layers of the skin are best studied using Monte Carlo modeling to evaluate dose to particular skin structures. This dosimetric study will provide insight on the severity of epidermal necrosis expression at particular skin depths and contribute to quantitative assessment of the degree of CRI as well as the efficacy of proposed radiation medical countermeasures for alleviation of CRI.
Funding Support, Disclosures, and Conflict of Interest: This project has been funded in whole or in part with Federal funds from the Biomedical Advanced Research and Development Authority, ASPR, DHHS, under Contract Nos. HHSO100201200007C and HHS010020130DD18C.
Monte Carlo, Surface Dose, Radiation Protection